Logo / banner / graphic design collective marketplace

I want a site made for me that is basically a freelance site but for strictly designers. Mostly logos / banners / web templates. All design. I want a place where people can come and sign up and upload examples of their work to their profile page and buyers that like certain designers work will hire them to make them a logo or a banner or a web template depending on what that certain designer specializes in. The buyer will place an order with the designer as well as send him or her instructions on how they want their logo or banner or web template to look. The money will not be immediately given to the designer, it will be up in the air, not in the buyers account anymore but not in the designers account yet. Once the designer finishes the design he will submit it for approval to the buyer but when the designer submits the finished product for approval the website will automatically apply a watermark to the picture so that the buyer can't just take the logo and cancel the order, but if the buyer approves the logo and clicks the approve button then the water marks will be removed. I will explain more to the qualified developer for this project. I am looking for someone who can do it cheap for me but with quality and someone who can also work with me to think of was to make it a a pretty much a self sustaining website that won't need customer service. So i will need security features to protect both parties of every deal. And the way i make money is once the order is accepted by the buyer i will get a percentage of the order. But for more info please submit to me what you can do. I have a few ideas on how i want it to look but i want someone that has some design skill that can work with me on that. Thanks